Out an about on a drive through the bush for Geo Dad’s birthday Geo Mum said “Stop! What is that?“ Although he won’t admit it, we know Dad rolled his eyes, Geo mum says that at least three or four times each trip either for flowers, rocks or just random curiosities. We do love that she notices things most people drive past. This time we all admit it is something interesting and it is worth a closer look.
Beware of Logging trucks, High fire danger periods and Tourists! Parking WP suggested.
Please respect the area and don’t climb on the bank, we want you to touch and feel the rocks with minimal damage.
So what are we looking at here? Geological maps have helped us identify this area and it’s black strip that stood out to Geo Mum as a minor Coal Seam in an upfaulted block of Lower Cretaceous age rocks belonging to the Strzelecki Group. Characteristically the Strzelecki Group is known for is . Cretaceous fluvial lithic sandstones, siltstones, with minor conglomerates and coal.
This cut in has provided us with a little window into the layers of the upfaulted block, additional to the minor Coal Seam, fine-grained volcanic ash, siltstone and sandstones.
We get ask all the time to keep our Earth Science lessons short so we have included a short Coal lesson!
Coal is the fossilised remains of ancient forests. Many of these forests built up deep layers of peat in swamps (wet, rotten plant matter) at their base over time. As millions of years pass, this peat and the fallen trees are squashed by sediment that builds up on top of them.
This squashing slowly turns into carbon-filled coal. The prime coal-forming time on Earth was during the perfectly named Carboniferous period (300-360 million years ago).
Coal burning is the main source of electricity in Australia. A particular problem is Victorian coal, while plentiful, is of low grade (brown coal) and is wetter than black coal, which causes extra pollution when burned.
The Minor deposits of Coal here have undoubtedly kept the Miners away!
Whilst there are many Earth Caches covering Coal as a topic we felt this was a unique chance to see up close a seam in it’s natural state. To log this Earthcache we require you to read the cache notes provided and to visually explore GZ, then, to the best of your ability message us with the following answers;
1. The presence of coal here suggests what was here millions of years ago?
2. Do you think the Coal you are seeing here today was formed in the aptly named Carboniferous period? Please explain why or why not.
3. See if you can find any coaly roots extending down into the rock from the coal layer? Please note by Coaly, we mean Black.
4. Feel the Coal layer, describe what it feels like, does it leave any residue on your fingers?
5. A photo of your Team, GPS near GZ with your log and answers. (optional)
You are welcome to log your answers straight away to keep your TB's and Stats in order but please message us with your answers within a couple of days. Cachers who do not fulfil the Earth Cache requirement will have their logs deleted.
Acknowledgements; Dr. Anne Felton, earthresources.efirst.com.au, coolaustralia.org, www.odec.ca.
